A hand-held power tool with a quickly-clamping device is generally known from U.S. Pat. No. 6,569,001 B2, which is an angular polishing machine provided with a hollow working mandrel therein. The hollow working mandrel is mounted with a clamping device movable along the axial direction of the mandrel between a clamping position and a releasing position, wherein the clamping device includes a clamping flange provided with a threaded pin at the middle part thereof for mating with a counter flange on the end of the hollow mandrel, so that the working element is clamped between the clamping flange and the counter flange. The hollow mandrel is further provided with a thrust component mating with the threaded pin. At the clamping position, the threaded pin is screwed into the screw thread of the thrust component and is held at this clamping position under the action of spring force; at the releasing position, the thrust component pushes the threaded pin so as to drive the clamping flange to overcome the action of spring force to disengage from the surface of the clamped working element. At this time, because there is no friction force when the clamping flange and the clamped working element rotate relative to each other, the threaded pin of the clamping flange can be manually screwed out of the thrust component without resorting to any accessories, and the working element can be expediently replaced.
Although this clamping device can substantially clamp the working element to the working mandrel of the hand-held tool without any auxiliary tools, this clamping device is only suitable for clamping the working element which is driven rotationally. If the working element is driven by a vibration device so that the working element swings fore-and-aft along the longitudinal axis of the working mandrel, then it results in a greater mutational torque creating along the two rotating directions and a huge impact, so that it is impossible to ensure that the working element is clamped sufficiently and firmly by a known clamping device.